Abstract Set Theory

by Thoralf A. Skolem, 1962, PDF

The Algebra of Logic

by Louis Couturat, 102 pages, 590KB, PDF

Algebraic Logic

by H. Andreka, I. Nemeti, I. Sain, 2003, 129 pages, 740KB, PDF

Algebraic Tools for Modal Logic

by Mai Gehrke, Yde Venema, 2001, 109 pp, 1.3MB, PDF

The Art of Logic

by Nuel Belnap, 2009, 314 pages, 950KB, PDF

Asymptotic Differential Algebra and Model Theory of Transseries

by M. Aschenbrenner, L. van den Dries, J. van der Hoeven, 2015, 727 pp, 5.6MB, PDF

Axiomatic Set Theory

by Michael Meyling, 2011, 36 pp, 340KB, PDF

Axiomatic Set Theory I

by A. C. Walczak-Typke, 2009, 128 pp, 730KB, PDF

Basic Concepts in Modal Logic

by Edward N. Zalta, 2011, 92 pp, 570KB, PDF

Book of Proof

by Richard Hammack, 2009, 270 pages, 1.2MB, PDF

Coalgebras and Modal Logic

by Alexander Kurz, 2002, 100 pp, 1.7MB, PDF

Coherence in Linear Predicate Logic

by K. Dosen, Z. Petric, 2010, 51 pages, 410KB, PDF

The Continuum and Other Types of Serial Order

by Edward V. Huntington, 1917, 90 pages, 6.6MB, PDF

Descriptive Set Theory

by David Marker, 2002, 105 pp, 630KB, PDF

Descriptive Set Theory

by Yiannis N. Moschovakis, 2009, 516 pages, 3MB, PDF

Elementary Set Theory with a Universal Set

by Randall Holmes, 2005, 240 pages, 780KB, PDF

An elementary theory of the category of sets

by F. William Lawvere, 2005, 36 pages, DVI/PS/PDF

forall x: An Introduction to Formal Logic

by P.D. Magnus, 2008, 160 pages, 0.6MB, PDF

Formal Logic

Wikibooks, 2009

Foundations of Mathematics

by Stephen G. Simpson, 2008, 123 pages, 750KB, PDF

A Friendly Introduction to Mathematical Logic

by Christopher C. Leary, Lars Kristiansen, 2015, 380 pp, 1.7MB, PDF

Fundamentals of Model Theory

by William Weiss and Cherie D'Mello, 2000

The Game of Logic

by Lewis Carroll, 1887

A Gentle Introduction to the Art of Mathematics

by Joseph Fields, 2009, 428 pages, 1.5MB, PDF

Hack, Hack, Who's There? A Gentle Introduction to Model Theory

by David Reid, 2016, 273 pp, multiple formats

Handbook of Modal Logic

by Patrick Blackburn, Johan van Benthem, Frank Wolter, 2006, 1260 pp, multiple PDF files

An Introduction to Good Old Fashioned Model Theory

by Harold Simmons, 2004, 180 pages, 660KB, PDF

Introduction to Logic

by Michal Walickil, 2006, 179 pages, 4.1MB, PDF

Introduction to Mathematical Logic

by Vilnis Detlovs, Karlis Podnieks, 2014, 240 pp, 1.1MB, PDF

Introduction to Mathematical Logic: A problem solving course

by Arnold W. Miller, 1996, 75 pages, 430KB, PDF

Introduction to Proof Theory

by Gilles Dowek, 2001, 82 pp, 620KB, PDF

An Introduction to Set Theory

by William A. R. Weiss, 2008, 119 pages, PDF/PS/DVI

Intuitionistic Logic

by Nick Bezhanishvili, Dick de Jongh, 2010, 57 pages, 370KB, PDF

Isabelle/HOL: A Proof Assistant for Higher-Order Logic

by T. Nipkow, L.C. Paulson, M. Wenzel, 2010, 223 pages, 1.2MB, PDF

Lecture Notes on the Lambda Calculus

by Peter Selinger, 2007, 106 pages, 460KB, PDF

Lectures on Linear Logic

by A. S. Troelstra, 1992, 215 pages, 47MB, PDF

Logic and Proof

by Lawrence C Paulson, 2002, 79 pages, 290KB, PDF

Logic for Computer Science

by Jean H. Gallier, 1986, 528 pages, 1.5MB, ZIP/PDF

Logic for Computer Science

Wikibooks, 2010, online html

Logic For Everyone

by Robert A. Herrmann, 2006, 124 pages, 1MB, PDF

Logics of Time and Computation

by Robert Goldblatt, 1992, 200 pages, 6.8MB, PDF

Mathematical Logic

by Stephen G. Simpson, 2008, 127 pages, 700KB, PDF

Metalogic

by Jan Wolenski, 2002, 35 pp, 270KB, PDF

Modal Logic of Strict Necessity and Possibility

by Evgeni Latinov, 2014, 264 pp, online reading

Model-Theoretic Logics

edited by J. Barwise, S. Feferman, 1985, PDF

Model Theory

by C. Ward Henson, 2010, 122 pages, 650KB, PDF

Model Theory, Algebra and Geometry

by Deirdre Haskell, Anand Pillay, Charles Steinhorn, 2000, 227 pages, PDF

Natural Topology

by Frank Waaldijk, 2012, 174 pp, 1.1MB, PDF

Notes on the Science of Logic

by Nuel Belnap, 2009, 227 pages, 750KB, PDF

Practical Foundations of Mathematics

by Paul Taylor, 1999

Predicative Arithmetic

by Edward Nelson, 1987, 201 pages, 5.3MB, PDF

The Principles Of Mathematics

by Bertrand Russell

A Problem Course in Mathematical Logic

by Stefan Bilaniuk, 2003, 166 pages, 0.7MB, PDF

Prolog Experiments in Discrete Mathematics, Logic, and Computability

by James Hein, 2005, 160 pages, 0.9MB, PDF

Proof, Sets, and Logic

by M. Randall Holmes, 2009, 207 pages, 750KB, PDF

Proof Theory and Philosophy

by Greg Restall, 2006, 168 pages, 1MB, PDF

Proofs and Concepts: the fundamentals of abstract mathematics

by Dave Witte Morris and Joy Morris, 2009, 220 pages, 1.8MB, PDF

A Second Course in Logic

by Christopher Gauker, 2010, 166 pages, 3MB, PDF

Set Theory

by Gary Hardegree, 2003, PDF

Sets, Groups and Knots

by Curtis T. McMullen, 2008, 56 pp, 330KB, PDF

Sets, Relations, Functions

by Ivo Duentsch, Guenther Gediga, 2000, 55 pages, 230KB, PDF

Symbolic Logic

by Lewis Carroll, 1897

Symbolic Logic: A First Course

by Gary Hardegree, 1999, PDF

Symbolic Logic: A Second Course

by Gary Hardegree, 2003, PDF

What is Mathematics: GĂ¶del's Theorem and Around

by Karlis Podnieks, 2013, 239 pp, 1.2MB, PDF